Fluorescence light source apparatuses which excite a phosphor by laser light and emit fluorescence emitted from the phosphor are currently known. For example, Patent Literature 1 describes a fluorescence light source apparatus configured so that a fluorescent plate constituting a phosphor and a heat dissipation substrate are bonded by a bonding material. Examples of the bonding material may include an organic adhesive, an inorganic adhesive, a low-melting-point glass and a metal brazing material. Of these, a metal brazing material is described to be desirably used because of high reflectance and a high heat transfer characteristic.